DPS sorcs have 2 heals, quick and long, if you dont have an interrupt up, use a knockback or a stun, whatever.
As someone who plays a madness sorc in pvp i can tell you that yes, there are times when a quick heal and a shield can turn a fight around, but i can also tell you that anyone playing their class well, will not allow me to heal myself.
I'd watch a pvp video or look at a thread for some helpful tips to improve your game.